Lightning arrester



` Jan. 31,v 1928.

A. L. ATHERTON LIGHTNING ARHESTER Filed sept. 19. 1922 Figl. I

J5 .3.3 as @4 mvENToR .Alfred L. Atherton.

WITNESSES:

ATTORNEY Patented Jan. 31, 1928.

UNITED STATES PATENT carica.

ALFRED L. ATKHERTON, OF PITTSBURGH, ENNSYLVANIA, ASSIGNOR TO VIESTING-HOUSE ELECTRC & MANUFACTURNG COMPANY, A CORPORATION' OF .PENNSYL- VANA.

LIG-HTNNG ARRESTEB.

Application filed September 19, 1922. Serial No. l389,087.

My invention relates to lightning arresters, more especially to themultiple-gap type commonly employed in alternating-current circuits.

It is among the objects of this invent-ion to provide an arrester whichis of simple compact structure, readily accessible and applicable toalternating-ernment transmission lines.

It is a further object of this invention to provide a struct-ure whichshall be relatively inexpensive to manufacture in production quantities.

Lightning arresters of the series multigap type heretofore employedfunction upon the principle of obtaining a. discharge of abnormal surgesfrom a line to ground through a series of arc gaps having a resistancein series therewith.i

My present invention is directed to a structure which comprises arelative .y large number of such discharge gaps, each having resistancein series therewith, but connected in parallel or shunt groups. rlhestructure is relatively simple and is contained wit-hin a compact unitto make it commercially applicable.

In the accompanying drawings consti- `tuting a part hereof and in whichlike reference characters designate like parts,

Fig. 1 is a plan view of a resistor element of a lightning arresterembodying the principles of my invention, and

Fig. 2 is a cross-sectional view of the lightning arrester taken alongthe lines H- H of Fig. l.

Referring to the drawing, the arrester may comprise a plurality ofinstal plates constituting electrodes having insulating spacer rings 31disposed therebetween, Resistor dislrs 32, provided with surfacecoatings 33 or non-arcing conductor material, such as brass, and havinga large number of parallel transverse slots or receses 34, are disposedbetween adajacent electrodes 30. The dimensions of the elctrodes 30 andthe spacer rings 31 are such as to provide suitable spaces or gap 35between the resistor surface coatings 33 and the metal-plate electrodes30, thus establishing a plurality of individual sparking surfaces 36 inshunt to said metalplate electrodes. Any number of such constructedlayers may be stacked in multiple to provide an arrester of thc desiredcapacit-y, as in Fig. 9,.

The function of these arresters is such that, when the device isconnected in a circuit, discharge will be effected, through theindividual sparking surfaces 36 and the several serially relatedsections of the resistors the rcsistances of which are suiiiciently highto limit the current-carrying capacity of each sparking surface 36 to asmall value, so that the continued iow of the line current, after anexcess-voltage discharge, is eifectively prevented, the discharge beingdistributed over awide area of low currentdensity, instead of beingconcentrated in a single point, as in a-rresters of the prior art. rlierelatively large number of gaps 35 built up in shunt groups thusincreases the discharge capacity to a relatively large degree withoutraisingthe current across each gap and without requiring the height ofconstruction heretofore employed in arrestors oi' the low-equivalenttype.

lt will be evident from the above dccription that a lightning arresterbuilt in accordance therewith provides an ei'iicient discharge path forabnormal voltages or surges on power 'transmission lines, therebyprotecting the insulation of electrical devices embodied in suchcircuits.

A further advantage is that such ay device provides a plurality of sparkgaps which, owing to the series resistances, are individually of a lowcurrent capacity but, as a unit, provide a relatively large currentcapacity for the size of the structure.

Athough have described a specific embodiment of my invention, it will beobvious to those skilled in the art that various modifications may bemade in the details of construction without departing from theprinciples herein set forth. For instance, any arrangement of resistorsto produce a plurality of spark gaps in shunt may be provided in placeof the structure herein described, or the devices illustrated may beenclosed within a suitable container or in other ways modilicd to adaptthem to the specific service in which they are to be used.

l claim as my invention:

l. A lightning arrester comprising a pair of electrodes having a gaptherebetween, one of said electrodes comprising resistance inaterialhaving its gap surface divided into a large number of sparking surfacesby means of a large number of slots, the resistances of the severalserially related sections of the resistance material beingsuffinientl),Y high to linut the current-carrying Capaoity of each ofthe said sparking surfaces to a small value, so that the total dischargeof thea'rresteris distributed-over a ,plurality of said sparkingsurfacesinsteadof 'being sparking Surfaces by ,means oi a large num-` ber ofslot/s, the yresistances oit -the several serially related sections ofthe resistance material being sueiently high to limit theeurrentcarrying Capacityl of each of the said sparking surfaces to asmall value, vso that the total discharge `of the arrester isdistributed over a plurality :of said .sparking surfaces instead ofbeing concentra-ted in a singlearo.

3. A lightning arrester comprising a group of resistor elementsarrangedin sideby-sirde relation to form parallel, substan-v tiallydistinet'eu'rrent discharge paths, an electrode member spaced from theends of said resistorelements to constitute a plurality of dischargegaps in series with said parallel paths, the resistance of each pathbeing .suiliciently large to resti-ict the current in each individualpath to a relatively small value, and the total number o't paralleldischarge paths being sufficient to provide la relatively largedischarge capacity.

In testimony whereof, have hereunto Ysubscribed my naine this 25th dayof `August ALFRED L. ATHERTON.

